Previously, boxes formed of paperboard material were made by severing the multi-layered material into individual boards and subsequently printing, cutting, and scoring in multiple stages of operations to form individual, two-dimensional box blanks. These limitations were addressed in U.S. Pat. No. 4,545,780, assigned to the assignee of the instant application, which patent discloses an apparatus and method of making cartons wherein the separate printing, cutting, and scoring stages are combined into a single, continuous operation. Despite this advancement in the art, however, it remains the case that printing both sides of box blanks in non-random fashion in the continuous operation of U.S. Pat. No. 4,545,780 is problematical.
Presently, the printing step is addressed to a single face of the box blanks only; customarily, the surface of the web of material constituting the outside of the finished box blank. This conventional printing operation comprises threading a first web of paperboard material through one or more printing decks for the application of desired indicia thereon in one or more colors, all as explained more fully in U.S. Pat. No. 4,545,780, the disclosure of which is incorporated by reference herein in its entirety.
While the inventors hereof have previously developed means for printing indicia on both faces of the box blank, these means have been of limited utility because it has heretofore not been possible, to their knowledge, to align the separate box blanks defined on each of the separate webs of paperboard material before they are joined together to define the unitary web from which the individual box blanks are cut, in consequence of which fact the resulting box blanks are characterized by properly aligned indicia on one surface thereof, and randomly oriented indicia on the opposite surface thereof.
It would therefore be desirable to have an apparatus and method for the continuous formation of paperboard box blanks wherein the printed indicia provided on the separate webs of paperboard material are aligned, or registered, before these separate webs are joined together to form the unitary web from which the box blanks are cut.